Battery pack

ABSTRACT

A battery pack for an electric appliance has a base body, a locking device for locking the base body to the electric appliance, at least one contact element for producing an electrical contact with the electric appliance, and a contact holding unit for holding the contact element. The locking device and the contact holding unit are fastened to the base body by a shared fastening module.

CROSS-REFERENCE TO A RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/696,266 filed on Apr. 4, 2007 now U.S. Pat. No. 7,670,171, which isincorporated here by reference and which provides the basis for a claimof priority of invention.

The invention described and claimed hereinbelow is also described inGerman Patent Application DE 102006018009.7 filed on Apr. 7, 2006. ThisGerman Patent Application, whose subject matter is incorporated here byreference, provides the basis for a claim of priority of invention under35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The invention is based on a battery pack for an electric appliance.

A battery pack for a handheld power tool is known. In order to lock thebattery pack to the handheld power tool, it is provided with a lockingdevice. The battery pack also includes contact blades that produce anelectrical contact between storage cells of the battery pack and thehandheld power tool in the locked position. These contact blades areheld by a contact holder in which counterpart connection means of thehandheld power tool engage in the locked position.

SUMMARY OF THE INVENTION

The invention is based on a battery pack for an electric appliancehaving a base body, a locking device for locking the base body to theelectric appliance, at least one contact element for producing anelectrical contact with the electric appliance, and a contact holdingmeans for holding the contact element.

According to one proposal, the locking device and the contact holdingmeans are fastened to the base body by means of a shared fasteningmodule. This makes it possible to advantageously reduce the assemblycost when assembling the battery pack, in particular by reducing thenumber of assembly steps. It is also possible to reduce the number ofcomponents, in particular for fastening the locking device and thecontact means to the base body. The term “fastening module” should beunderstood in this context to particularly mean a module that isembodied as distinct from the base body and that represents a fasteninginterface between the locking device, the contact holding means, and thebase body.

The fastening module is suitably embodied of one piece. Preferably, ithas a fastening means for fastening to the base body. For example, thebase body is embodied as the housing of the battery pack. In addition,the fastening module preferably has fastening means provided forfastening the locking device and the contact holding means.

The locking device and the contact holding means are advantageouslyfastened directly to the fastening module. The locking device, thecontact means, and the fastening module suitably constitute a structuralunit that can be preassembled outside of the base body. The locking unitand the contact holding means can be fastened to the fastening modulebefore the fastening module is fastened along with the locking deviceand the contact holding means to the base body. The fastening module canbe embodied in the form of an intermediate piece, e.g. an intermediateflange.

According to another proposal, the contact holding means is embodied asintegrally joined to the fastening module. This makes it possible toeliminate additional fastening components and thus to reduce the amountof space required and the number of assembly steps. It is also possibleto achieve a particularly effective support of a contact element.Alternatively or in addition, the locking device can be embodied asintegrally joined to the fastening module. Moreover, the contact holdingmeans can be embodied as detachable from the fastening module; thecontact holding means can be fastened to the fastening module by meansof a nonpositive, frictional engagement, a material adhesion, and/orparticularly advantageously by means of a form-locked engagement, whichmakes it possible to achieve a simple fastening.

If the fastening module is provided for a toolless fastening of thelocking device, then the assembly can be further simplified and easilyautomated.

A particularly simple and secure fastening of the locking device can beachieved if the locking device is fastened to the fastening module bymeans of a form-locked engagement. For example, the locking device canbe fastened to the fastening module through the production of a detentconnection, e.g. a snap connection. It is also conceivable to fasten thelocking device by means of a nonpositive, frictional engagement and/or amaterial adhesion.

According to another proposal, the locking device is situated on thefastening module in a movable fashion. This enables a sturdy support ofthe locking device in its movements, e.g. when a user actuates it.

In this connection, a structurally simple locking mechanism can beachieved if the locking device used is situated on the fastening modulein pivoting fashion.

In an advantageous modification of the invention, the fastening moduleencompasses at least a subregion of the locking device. This makes itpossible to achieve a compact design of the battery pack and a sturdyand secure support of the locking device on the fastening module. If thelocking device is situated on the fastening module in a movable, inparticular pivoting, fashion, then the subregion of the locking devicecan constitute a sliding surface that slides against the fasteningmodule when the locking device is moved. In particular, the subregioncan be embodied in the form of a pivot axle of the locking device inwhich a section of the fastening module encompasses the pivot axle. Thissection can advantageously also serve as a fastening element for thefastening of the locking device.

The locking device advantageously has a locking means that is fastenedto the fastening module. This makes it possible to achieve a sturdy andsecure support of the locking means by means of the fastening module.

According to another proposal, the locking means is embodied in the formof a spring element. This makes it possible for the locking means to beheld in a desired position due to an inherent force of the locking meansand thus makes it possible to achieve a structurally simple embodimentof the locking device. The locking element is preferably embodied in theform of a metal spring, which permits the use of conventional, sturdy,and inexpensive locking means. For example, the spring element isembodied in the form of a flexion spring, in particular a leaf spring.

In this connection, the spring element according to the inventionincludes a detent shape. This makes it possible to achieve aparticularly sturdy and secure locking mechanism.

In another embodiment of the invention, the locking device has a lockingmeans and an actuating means for actuating the locking means; thelocking means connects the fastening means to the fastening module. Thismakes it possible to achieve a particularly compact and simpleembodiment of the locking device. Preferably, the actuating means isfastened to the actuating module. In addition, the actuating means issituated on the fastening module in a movable, e.g. pivoting, fashion.

Furthermore, it is possible to achieve a particularly compact embodimentof the battery pack if the battery pack has at least one storage cell;the locking device, the contact holding means, and the fastening moduleconstitute a structural unit that at least partially encompasses thestorage cell.

The invention also proposes an electric appliance, in particular ahandheld power tool, having an electric appliance base body, e.g. agrip. This electric appliance advantageously has a battery pack that canbe detached from the electric appliance base body and that has a basebody, a locking device for locking the base body to the electricappliance base body, at least one contact element for producing anelectrical contact with the electric appliance base body, and a contactholding means for holding the contact element; the locking device andthe contact holding means are fastened to the base body by means of ashared fastening module. This makes it easily possible to achieve a lowassembly cost. The electric appliance can also be embodied in the formof a charging unit for charging the battery pack.

Other advantages ensue from the following description of the drawings.An exemplary embodiment of the invention is shown in the drawings. Thedrawings, the description, and the claims contain numerous features incombination. Those skilled in the art will also suitably consider thefeatures individually and unite them in other meaningful combinations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cordless power screwdriver and a battery pack locked tothe handheld power tool, in accordance with the present invention,

FIG. 2 is a perspective view of the battery pack from FIG. 1 inaccordance with the present invention,

FIG. 3 shows the battery pack with a housing shell removed, revealingthe internal components in accordance with the present invention,

FIG. 4 shows a locking device, a contact holding means, and storagecells of the battery pack in accordance with the present invention, and

FIG. 5 shows the contact holding means and the locking device from FIG.4 in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an electric appliance 10 embodied in the form of a handheldpower tool. The handheld power tool is embodied in the form of acordless power screwdriver. It has an electric appliance base body 14 towhich a tool holder fitting 12 is fastened. The electric appliance basebody 14 also comprises a grip 16 to which a battery pack 18 is locked.The battery pack 18 includes a base body 20, which is embodied as thehousing of the battery pack 18. The battery pack 18 is embodied in theform of a sliding battery pack. In order to lock the battery pack 18 tothe grip 16, the base body 20 is slid in a sliding direction 24 alongthe grip 16, in fact along a lower outer surface 23 of the grip 16extending essentially perpendicular to the longitudinal direction of thegrip 16.

Once this position is reached, the battery pack 18 is locked to the grip16 by means of a locking means 32 of a locking device 30 (FIGS. 2through 5). The locking means 32 has a detent shape 44. In its lockedposition shown in the drawing, this detent shape is engaged in a detentrecess, not shown in detail, of the grip 16. The battery pack 18 can beunlocked from the electric appliance 10 by actuating an actuating means34 (FIG. 2) of the locking device 30, which withdraws the detent shape44 from the grip 16. After the battery pack 18 has been unlocked, thebase body 20 can be separated from the electric appliance 10, in fact bysliding the base body 20 in a removal direction 22 along the lower,outer surface 23 of the grip 16. The sliding direction 24 and theremoval direction 22 are oriented essentially perpendicular to thelongitudinal direction of the grip 16.

FIG. 2 is a perspective view of the battery pack 18. The drawing showsthe locking means 32 and the base body 20 embodied as a housing. Thedetent shape 44 of the locking means 32 protrudes up from a surface 35of the base body 20, which surface is embodied in the form of a contactsurface and which, when the battery pack 18 is in the locked position,rests against the grip 16, in particular against the outer surface 23 ofthe grip 16. Adjoining the surface 35, the drawing shows a surface 37 ofa contact holding means 36. This contact holding means 36 serves to holdconducting contact elements 66 (FIG. 5) in order to produce anelectrical contact between the electric appliance 10 and storage cells52 situated in the base body 20 (FIG. 3). When the base body 20 is slidalong the grip 16, counterpart connection means of the electricappliance 10 engage in slots of the contact holding means 36 in whichthey come into contact with the contact elements 66 of the battery pack18. The base body 20 is also provided with a guiding means, which isembodied in the form of two guide rails 26. One guide rail 26 is visiblein the figure. This guide rail 26 is integrally formed onto a wall of anupper housing shell 28 of the base body 20. The upper housing shell 28is attached to a lower housing shell 29 (see FIG. 3). When the base body20 is slid along the grip 16, the guide rails 26 each engage in a recessof the grip 16 (not shown), producing a groove/spring connection withthe grip 16.

During the sliding process, the base body 20 is supported by the grip16, thus making it possible to prevent the battery pack 18 from beingdropped as it is guided along the grip 16. In order to unlock thebattery pack 18 from the grip 16, the battery pack 18 is also providedwith the actuating means 34, which is embodied in the form of apushbutton. The unlocking mechanism will be described in detail inconjunction with the subsequent figures.

FIG. 3 shows the battery pack 18; the upper housing shell 28 of the basebody 20 has been removed from the lower housing shell 29. The drawingshows the upper surface 37 of the contact holding means 36 (see FIG. 2);the locking device 30 with the actuating means 34 and the locking means32, which has the detent shape 44; and storage cells 52.

In order to fasten the locking device 30 and the contact holding means36 to the base body 20, namely to the lower housing shell 29, thebattery pack 18 is provided with a fastening module 38. This fasteningmodule 38 constitutes a fastening interface between the locking device30 and the contact holding means 36 on the one hand and the base body 20or lower housing shell 29 on the other. This fastening module 38,together with the locking device 30, the contact holding means 36, and acontact holding means 60 shown in FIG. 4, constitutes a structural unit68 (FIG. 4), in particular a cohesive structural unit 68 that isfastened to the base body 20. To this end, the fastening module 38 hasfastening means 42 for fastening the locking device 30 to the fasteningmodule 38 on the one hand and fastening means 46 for fastening thefastening module 38 to the base body 20 on the other.

In this exemplary embodiment, the contact holding means 36 is integrallyformed onto the fastening module 38. The fastening module 38 has a firstsubregion that is offset relative to the surface 37 of the contactholding means 36. This subregion has a slot into which the locking means32 is slid and clamped firmly in place. The subregion also has two snaparms, which constitute the fastening means 42 for fastening the lockingdevice 30. A subregion 40 of the actuating means 34 engages in detentfashion or is snapped into these fastening means 42. The actuating means34 of the locking device 30 is situated on the fastening module 38 in apivoting fashion. To this end, the subregion 40 is embodied as a pivotaxle. The subregion 40 also constitutes a sliding surface that slidesagainst the fastening means 42 during a pivoting of the actuating means34.

The fastening module 38 also has an additional subregion, which isembodied in the form of a plateau 43 supported on one of the storagecells 52. The plateau 43 has a recess that constitutes the fasteningmeans 46 for the fastening of the fastening module 38 to the base body20. A protrusion of a screw socket 56 of the lower housing shell 29,which socket is not visible in the figure, is clamped in this recess. Bymeans of this nonpositive, frictional engagement, the fastening module38 is secured to the base body 20. The screw socket 56 of the housingshell 29 and the recess of the fastening means 46 also permit afastening screw to pass through during an assembly of the battery pack18 in order to fasten the upper housing shell 28 to the lower housingshell 29.

The lower housing shell 29 also has additional screw sockets 56 on aside of the housing shell 29 opposite from the locking device 30. Inaddition, a cylindrical electrical component 48 is fastened to theplateau 43. This component serves to prevent short-circuiting of thebattery pack 18 and to this end, is connected to the storage cells 52via an electrical connection 50 and conducting contacts 54 of thestorage cells 52. The electrical component 48 is situated so that itengages in detent fashion between snap arms of the plateau 43 (also seeFIG. 5). The fastening module 38 can have additional electricalcomponents fastened to it such as an electrical encoding foridentification of the battery pack 18.

In an alternative embodiment, it is conceivable for the contact holdingmeans 36 to be embodied as detachable from the fastening module 38. Inthis case, the fastening module 38 has fastening means for fastening thecontact holding means 36. In another variant, it is conceivable for thelocking device 30 to be embodied as integrally joined to the fasteningmodule 38.

FIG. 4 shows a view of the battery pack 18 in which the lower housingshell 29 has been removed. The drawing also shows an additional contactholding means 60 in addition to the components described above inconjunction with FIG. 3. In the mounted position of the battery pack 18,this contact holding means 60 is situated in an opening, not shown, ofthe lower housing shell 29. The contact holding means 60 is integrallyformed onto the fastening module 38. The contact holding means 60 holdscontact elements 61, which are embodied in the form of bell-shapedcontacts. When the storage cells 52 are being charged, these contactelements 61 produce an electrical contact with counterpart connectionmeans of a charging unit that is not shown.

The contact elements 61 are visible to the user through theabove-mentioned opening of the lower housing shell 29. The contactholding means 60 is electrically connected to the storage cells 52 viaan electrical connection 64 and the electrical component 48. In anotherexemplary embodiment, it is conceivable for the contact holding means 60to be embodied as detachable from the fastening module 38 and to befastened to the fastening module 38. It is also conceivable for thebattery pack 18 to be embodied without contact holding means 60. Thefigure also shows an electrical connection 62 through which the storagecells 52 are electrically connected to the contact holding means 36.

The locking means 32 is embodied in the form of a metallic leaf springserving as spring element. As described above, this spring element isfastened to the fastening module 38 on the one hand and to the actuatingmeans 34 on the other. The locking means 32 is fastened to the actuatingmeans 34 so that when the actuating means 34 is pivoted, the lockingmeans 32 is carried along with it and when pressure is exerted on thedetent shape 44, the locking means 32 engages further in the actuatingmeans 34. Starting from the locked position of the battery pack 18 shownin FIG. 1, in which the detent shape 44 of the locking means 32 isengaged in the electric appliance 10 in detent fashion, in order tounlock the battery pack 18, the user actuates the actuating means 34.

In this case, the user exerts an actuating force on the actuating means34 in the direction toward the bottom of the lower housing shell 29, infact in the actuating direction 55. In so doing, the actuating means 34is pivoted around its subregion 40 embodied in the form of a pivot axle.The locking means 32 is carried along with this pivoting motion, thusmoving the detent shape 44 downward in the actuating direction 55. Thedetent shape 44 is withdrawn from the electric appliance 10, thusunlocking the battery pack 18 from the electric appliance 10.

When the battery pack 18 is unlocked from the electric appliance 10, asthe base body 20 is slid along the handle 16, the surface 23 of the grip16 pushes the locking means 32 into the outer surface 35 of the housingshell 28 until the detent shape 44 engages in the electric appliance 10.When pressure is exerted on the detent shape 44, the locking means 32engages further in the actuating means 34, as described above.

FIG. 5 shows the fastening module 38 to which the locking device 30 isfastened and onto which the contact holding means 36 is integrallyformed. The drawing shows the plateau 43 to which the electricalcomponent 48 is fastened and onto which the fastening means 46 isformed. An additional fastening means 46 is situated on a side of thefastening module 38 oriented away from the plateau 43. The drawing alsoshows the electrical contact elements 66 contained in the slots of thecontact holding means 36. The contact elements 66 are extrusion-coatedwith plastic during the manufacture of the fastening module 38. Thecontact holding means 36 has an additional fastening means 58 formedonto it, embodied in the form of a hook provided for fastening to theupper housing shell 28.

In the preparations for assembling the battery pack 18, the structuralunit 68, which is comprised of the locking device 30 and the fasteningmodule 38 with the contact holding means 36 and 60 integrally formedonto it, is preassembled separately from the base body 20. To this end,the fastening means 34 is attached to the fastening module 38 in atoolless fashion, in fact by means of the subregion 40 embodied in theform of a pivot axle engaging in detent fashion or being snapped intothe fastening means 42 embodied in the form of snap arms. Then thelocking means 32 embodied in the form of a spring element is slid intothe fastening module 38 on the one hand and into the fastening means 34on the other.

During assembly of the battery pack 18, this cohesive structural unit 68is placed onto the storage cells 52. A soldering procedure produceselectrical connections between the contact holding means 36, 60 and thestorage cells 52. When placed onto the storage cells 52, the structuralunit 68 encompasses at least one of the storage cells 52 (see FIG. 4).The set of storage cells 52, together with the structural unit 68, isthen inserted into the lower housing shell 29. In so doing, shapes oftwo of the screw sockets 56 of the lower housing shell 29 are clampedinto the fastening means 46 of the fastening module 38. Then the upperhousing shell 28 is placed onto the lower housing shell 29 and thehousing shells 28, 29 are screwed to each other, with the screws passingthrough the screw sockets 56 of the housing shell 29.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the type described above.

While the invention has been illustrated and described as embodied in abattery pack, it is not intended to be limited to the details shown,since various modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

1. A battery pack for an electrical appliance, comprising a base body; alocking device for locking said base body to the electrical appliance;at least one contact element for producing an electrical contact withthe electrical appliance; contact holding means for holding said contactelement; and a shared fastening module by which said locking device andsaid contact holding means are fastened to said base body, wherein saidbase body has an upper housing shell including guiding means and a lowerhousing shell, wherein said contact holding means is configured asintegrally joined to said fastening module; and an additional contactholding means, which is separate and distinct from said contact holdingmeans, wherein the additional contact holding means is integrally formedonto the fastening module.
 2. A battery pack as defined in claim 1,wherein said fastening module is provided for a toolless fastening ofsaid locking device.
 3. A battery pack as defined in claim 1, whereinsaid locking device is attached to said fastening module by aform-locked engagement.
 4. A battery pack as defined in claim 1, whereinsaid fastening module includes at least a subregion of said lockingdevice.
 5. A battery pack as defined in claim 1, wherein said lockingdevice has locking means and actuating means for actuating said lockingmeans, said locking means connecting said actuating means to saidfastening module.
 6. A battery pack as defined in claim 1; and furthercomprising at least one storage cell, said locking device, said contactholding means and said fastening module forming a structural unit thatat least partially encompasses said storage cell.
 7. A battery pack asdefined in claim 1, wherein the contact holding means comprises aplurality of slots for engaging counterpart connection means of theelectrical appliance.
 8. A battery pack as defined in claim 1, whereinsaid locking device is situated on said fastening module in a moveablefashion.
 9. A battery pack as defined in claim 8, wherein said lockingdevice is situated on said fastening module in a pivoting fashion.
 10. Abattery pack as defined in claim 1, wherein said locking device haslocking means that is fastened to said fastening module.
 11. A batterypack as defined in claim 10, wherein said locking means is configured asa spring element.
 12. A battery pack as defined in claim 11, whereinsaid spring element includes a detent shape.
 13. An electricalappliance, comprising an electrical appliance base body; and a batterypack detachable from said electrical appliance base body, said batterypack including a base body, a locking device for locking said base bodyto the electrical appliance, at least one contact element for producingan electrical contact with the electrical appliance, contact holdingmeans for holding said contact element, and a shared fastening module bywhich said locking device and said contact holding means are fastened tosaid base body, wherein said base body has an upper housing shellincluding guiding means and a lower housing shell and wherein saidcontact holding means is configured as integrally joined to saidfastening module wherein an additional contact holding means, which isseparate and distinct from said contact holding means, is arranged on alower side of the fastening module, which in an assembled state, facesthe lower housing shell.